(a) Field of the Invention
The present invention concerns a compression circuit for a low pressure low temperature gaseous fluid, for example, helium, from a first container containing said fluid in gaseous and liquid phases at a first pressure and first temperature, the circuit comprising, in a line connecting the first container to a heating device, at least two compressors mounted in series, the first container being fed by a second container having said fluid in gaseous and liquid phases at a second pressure and a second temperature higher than the first pressure and temperature, respectively.
(b) Description of Prior Art
In some applications, for example for refrigerating supraconductor elements in accelerators of particles, there is a need to be able to rely on a fluid at very low temperatures, lower than 4.2K, the pressure of the fluid, under these conditions, being also very reduced, to lower than 20 hPa. In order to reintroduce the gaseous fluid at this very low pressure in the cycle of refrigeration, at least two, in practice a plurality of cryogenic compressors mounted in series, are used according to an arrangement which is difficult to master by reason of the instability which may appear along the line.